Calcium: II. Role in keratoconus.

Calcium metabolism was assessed in 18 keratoconic and 18 age- and sex-matched control subjects using four types of analyses: diet, serum, urine and hair. There was no significant difference between the two groups for dietary intake, serum, urine and hair parameters of calcium, and related minerals. Although the control group had a higher daily intake of vitamin D than did the keratoconus group, the serum levels of the active vitamin D hormone, 1,25-(OH)2 vitamin D3, were the same in both groups. These findings suggest that systemic calcium or vitamin D metabolic imbalances are not involved in maintaining eyes in a keratoconic state.